JPS62214541A - Photomagnetic recording device - Google Patents

Abstract

PURPOSE:To execute rewriting of information at a high speed by executing an erasing operation by irradiating like DC a laser light to a sector being previous by one, by a preceding light spot, and recording the information to a sector which is positioned at present by a following light spot. CONSTITUTION:A beam 3 made incident from an optical system 2a which is set in the inside of a photomagnetic head housing 2 is condensed onto a recording track on a recording medium 5 through a condensing lens 4, and a light spot 6 is formed. The spot 6 exists in a magnetic field of a bias magnetic field coil 7, and by irradiating like DC the beam 3 by an input signal from an erasion controlling circuit 30, information which is recorded previously is erased, as a medium 5 moves. A beam made incident from an optical system 2b is condensed onto a recording track through a condensing lens 9 which is placed in a position running along the recording track against the lens 4, and also in a position which has been separated by one sector length against the moving direction of the medium 5, and a light spot 10 is formed. In such a way, new recording is executed to the part which is erased by the spot 6, and rewriting can be executed at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magneto-optical recording device that records, erases, and reads information on a recording medium using both optical means and magnetic means.

[Conventional technology]

A laser beam is used as a light source, and this laser beam is modulated with a pulsed signal from an external information source, and the magneto-optical effect is used to record the information on the recording medium in duplicate, or to record information that has already been recorded. In magneto-optical recording devices that read out data, recording is performed by applying a bias magnetic field in the opposite direction to a recording medium that has been previously magnetized in one direction, and then focusing a laser beam on a minute optical spot on the surface of the recording medium using a condensing lens. narrowed down and heated according to the pulse signal to reverse the magnetization of this part,
This is performed by forming a magnetization reversal pattern according to the pulsed signal. On the other hand, to erase information that has already been recorded, apply a bias magnetic field in one direction and irradiate the laser beam with direct current to remagnetize the recording medium in the same direction for the section of the recording track that is to be erased. This is done by

[Problem that the invention seeks to solve]

However, conventional magneto-optical recording devices have only one condensing lens and one optical spot for writing, reading, and erasing, so in order to rewrite already recorded information, it is necessary to Once erased, new information must be written after waiting for the disk to rotate to its original position, making it impossible to rewrite information at high speed. Conversely, even in the method of reversing the bias magnetic field using information while irradiating a laser beam with direct current, the inductance of the bias magnetic field generation coil makes it difficult to perform high-speed magnetization reversal, making it difficult to record information at high speed. However, its performance as an external storage device for computers was not sufficient.

A method for condensing two beams and controlling the beam using one condensing lens has been proposed for purposes other than the present invention, but in this method, the distance between two light spots is The distance between the two optical spots is extremely short, several tens of micrometers, and it is difficult to generate a magnetic field that reverses between the two optical spots, making it impossible to perform erasing and recording at the same time.

The purpose of the present invention is to eliminate the above-mentioned drawbacks and to
To provide a magneto-optical recording device capable of high-speed recording, reproduction, and erasing, in which new information can be written immediately after erasing already recorded information.

[Means for solving problems]

The present invention alternately changes the amount of light condensed onto a recording medium via a condensing lens in a binary manner, and applies a bias magnetic field in the perpendicular direction to the recording medium at the condensing position. In the magneto-optical recording device for recording optical information by changing the magnetization in the perpendicular direction of a recording medium, the magneto-optical head has two condenser lenses in a direction along the recording trunk; and bias magnetic field generating means for generating a reversible bias magnetic field in which the magnetic field in the perpendicular direction to the recording medium is in the same direction at the positions of the two light spots condensed by the two condenser lenses; The distance between the light spots is set to 1 on the recording medium track.
By making the bias field equal to the sector length and reversing the direction of the bias magnetic field every time the two light spots pass through one sector, the first light spot leading in the relative position with respect to the recording medium The information already recorded in the previous sector is erased, and at the same time, new information is recorded in the sector currently located by the second light spot of the two light spots. conduct,
It is characterized by being able to simultaneously record and erase information in sector units.

[Effect]

Two optical spots focused by two focusing lenses are made to follow the same recording track, and at the same time, the interval between the two spots is made equal to the sector length, and a bias magnetic field is generated in the same direction for the two spots. Then, by switching the direction in sector units, in the relative movement between the recording medium and the light spot, the preceding light spot direct-currently irradiates the sector with the laser light,
The erasing operation is performed, and the laser beam is modulated and irradiated according to the recorded information to the sector currently located by the optical spot to be followed, and the information is recorded.The erasing and recording operations are performed sector by sector. You can proceed in parallel with
High-speed rewriting of information becomes possible.

〔Example〕

FIG. 1 is a conceptual diagram showing one embodiment of the present invention.

This magneto-optical recording device includes first and second optical systems 2a and 2 that generate beams, respectively, in a magneto-optical head housing 1.
b, and first and second condensing lenses 4 that condense the beam.
．． 9, a bias magnetic field coil 7 for generating a bias magnetic field provided in front of these condenser lenses, a condenser lens 4,
actuator 41.91 provided for 9. A first optical system 2 is provided outside the magneto-optical head housing 1.
an erasure control circuit 3o that supplies an input signal to a, and a recording/reproduction control circuit 50 that supplies an input signal to the second optical system 2b.
and first and second beam position control circuits 35.55
and a coil drive circuit 60 that drives the bias magnetic field coil.
and is provided.

A first optical system 2a set inside the magneto-optical head housing 1
The first beam 3 that enters the recording medium 5 is focused onto a recording track on a recording medium 5 via a first condensing lens 4 to form a minute first light spot 6 . The optical spot 6 is in the bias magnetic field generated by the bias magnetic field coil 7,
By direct-currently irradiating the beam 3 in response to an input signal from the erasure control circuit 30, as the recording medium 5 moves (the direction is indicated by an arrow 51 in the figure), the portion of the recording track irradiated by the beam 3 is It is magnetized in a fixed direction determined by a bias magnetic field, and previously recorded information is erased.

The second beam 8 entering from the second optical system 2b is
A second condenser lens 9 is disposed along the recording track and one sector length away from the condenser lens 4 in the direction in which the recording medium 5 moves. The light is focused on the recording track to form a minute second light spot 10 at a position one sector away from the first light spot 6.

At this time, the bias magnetic field coil 7 is connected to the coil drive circuit 6
0, the light spot 6 and the light spot 10 are
Every time one sector passes, the direction of the generated magnetic field is reversed. Since the optical spot 10 is also in the bias magnetic field generated by the bias magnetic field coil 7, by reversing the bias magnetic field for each sector, the magnetization direction erased by the first optical spot 6 and the second optical spot 10 are Since the direction of the bias magnetic field is opposite to the direction of the bias magnetic field when information is recorded by
As the recording medium 5 moves, a magnetization reversal pattern corresponding to the pulsed signal is formed in the portion erased by the first light spot 6 on the recording track, and new information is recorded.

At this time, focus control is performed to always optimally focus the first and second beams 3.8 on the recording medium surface, and the focused first and second light spots 6.10 are recorded. Tracking control for following a track is performed using actuators 41 and 9 provided for the condenser lens 4.9, similar to the control in a conventional magneto-optical head with one condenser lens.
1. This is performed by a servo control mechanism consisting of position detectors (not shown) in each direction provided in the optical systems 2a and 2b, and first and second beam position control circuits 35 and 55.

FIG. 2 is a waveform diagram showing the operating waveforms of FIG. 1.

The sector formant within a track is composed of a preformat area 61 formed in advance with unevenness, etc., and a data area 62 in which the user records data. By applying a bias magnetic field to the sectors described above so that its direction is reversed for each sector, as shown by arrows 7o and 71 in FIG. 1, the erasing beam is
As indicated by reference numeral 63, an erasing operation is performed on the data area to erase already recorded data.

Subsequently, the recording beam performs a recording operation with a time delay of one sector in the erasing operation, as shown by reference numeral 64, and new data is immediately recorded in the area erased by the erasing beam. . At this time, if the recording medium is disk-shaped, if the rotation of the disk is controlled so that the circumferential speed of the disk is constant, the interval between the first light spot and the second light spot can be adjusted to the sector. This makes it possible to simultaneously record and erase information in sector units over the entire circumference of the disk.

〔Effect of the invention〕

With the configuration described above, the optical system can erase information that has already been recorded in the preceding optical spot in sector units, and record new information in the following optical spot in parallel. A magnetic recording device is obtained, which enables high-speed rewriting of information.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of a magneto-optical recording device according to the present invention, and FIG. 2 is a waveform diagram showing operating waveforms of FIG. 1. ■・・・・・Magneto-optical head housing 2・・・・・Optical system 3・・・・First beam 4・・・・・First beam Optical lens 5... Recording medium 6... First light spot 7... Bias magnetic field coil 8...
...Second beam 9...Second condensing lens 10...Second light spot 41.91...Actuator 35.55...No. 1 and 2nd beam position control circuit

Claims (1)

[Claims] (1) Alternately changing the amount of light condensed onto a recording medium via a condensing lens in a binary manner, and applying a bias magnetic field in a direction perpendicular to the recording medium at the condensing position. In the magneto-optical recording device for recording optical information by changing the perpendicular magnetization of a recording medium, there is provided a magneto-optical head having two condensing lenses in a direction along a recording track; 2 condensed by the condensing lens of
bias magnetic field generating means for generating a bias magnetic field in which a magnetic field perpendicular to the recording medium is in the same direction and reversible at two optical spot positions, and the interval between the two optical spots is set on the recording medium track. , and the direction of the bias magnetic field is reversed every time the two light spots pass through one sector, so that the first light spot leads in the relative position with respect to the recording medium. For the previous sector,
At the same time as erasing the information that has already been recorded,
A magneto-optical recording device that records new information in the currently located sector using the second light spot of the two light spots, and is capable of simultaneously recording and erasing information on a sector-by-sector basis. .